The two wide holes in the white area and the two wide holes above the white area appear to be for the contains lead signs. The white area looks to be where a RD-119 decal was applied at one time, then the green paint was applied over the decal and then decal was removed
if that makes sense. The two close together holes in the white area were undoubtedly drilled for some other purpose. Just my two cents.....

Wanted: Champion Spark plug, Shell, Pennzoil, Kendall, and Woco Pep signs...Dale Stephens